Genesyscloud_report_definition 400 on custom metric

Why does this setting trigger a 400 bad request? trying to push a custom report definition via terraform.

env: us-1 prod
provider: genesys 1.15.4
tf: 1.6.5

the error is
POST /api/v2/analytics/reports/definitions returns 400
{“errors”:[{“code”:“bad_request”,“message”:“validation failed for field metric_id”}]}

here is the block

resource “genesyscloud_report_definition” “custom_wait_time” {
name = “Custom Wait Time Analysis”
description = “custom metric test”
type = “custom”

columns {
id = “metric:wait.time.avg”
display_name = “Avg Wait”
}

filters {
id = “metric:queue.id”
type = “in”
values = [var.queue_id]
}
}

the metric id metric:wait.time.avg exists in the ui. i can create it manually in the admin portal without issue. but the api rejects it via terraform.

tried changing the type to ad-hoc but same result.

is there a specific format for the metric id in the api vs the ui? or is this a known bug with the provider version?

logs attached.

thanks.